But the law states that the defendant can argue for a lesser punishment if an evaluator recommends treatment of the offender in a local community.

In his decision, Judge McKeon, of Valley County District Court, cited a report prepared by Michael Sullivan, a specialist, who said the defendant could be "safely treated" in the community, court documents showed.

According to the records, the prosecution did not contest the findings.

'Not a monster'

The judge also cited a letter from the victim's mother, in which she acknowledged the "horrible" nature of the crime, but asked for leniency.

"He has two sons that still love him and need their father in their lives, even with very understandable restrictions. I would like to see my children have an opportunity to heal the relationship with their father.

"He is not a monster, just a man that really screwed up and has been paying in many ways since and will continue to have to pay through this justice system and with the loss of family and friends and his own conscience."

The girl's maternal grandmother also wrote a letter to the court, saying: "What [the defendant] did to my granddaughter was horrible, and he should face consequences.

"But his children, especially his sons, will be devastated if their dad is no longer part of their lives."

Court records said the victim did not attend the sentencing hearing, NPR reported, and that no-one testified on her behalf.

On 17 October, Judge McKeon sentenced the man to 30 years in prison, suspended, plus 60 days in a county jail. As he had already spent 17 days in prison, the jail sentence came to 43 days.

The sentence included many requirements, including his public registration as a sex offender, attendance at a sex-offender treatment programme and payment for his daughter's medical expenses.

Mr McKeon has defended himself from the criticism, AP news agency reported, saying the plea agreement allowed for a lesser jail sentence, depending on the results of a psychosexual evaluation.

He also noted the victim's mother and grandmother letters to the court.

The petition asking for his removal considers his decision "horrible" and the sentencing "light", saying: "Sixty days in prison with a suspended 30-year sentence does not match the crime and fails to acknowledge the horrors the victim had to endure.

"The victim only had the justice system on her side, and it failed her."

To impeach a judge in Montana, two-thirds of the state Legislature must vote for it, or the state's judicial standards commission may recommend it to the state Supreme Court, according to the National Center for State Courts.